In order to supply all passengers onboard an aircraft with adequately cooled drinking water, usually several drinking water provisioning devices are provided in the area of the aircraft's passenger cabin. Each of these drinking water provisioning devices comprises a reservoir connected with a central drinking water supply system for the intermediate storage of the fed-in drinking water from the drinking water supply system. For the purpose of cooling down the intermediately stored drinking water in is the reservoir to a desired dispensing temperature, a refrigerating machine is employed. The drinking water in the reservoir may for example, be cooled down to the desired dispensing temperature by means of a cold steam process using a compressor, or by means of Peltier elements. The waste heat which is generated thereby is exhausted to the ambient air and usually has to be drawn off by means of an evacuation system in order to ensure an adequate air exchange in the area of the refrigerating machine and the reservoir and to avoid the overheating of the refrigerating machine as well as of further components which are arranged in the environment of the refrigerating machine. When the drinking water which is intermediately stored in the reservoir has reached the desired cool dispensing temperature, the drinking water may be withdrawn via a dispensing point which is normally arranged in an immediate spatial vicinity to the reservoir.
Such known drinking water provisioning devices are disadvantageous in that the refrigerating machine as well as the evacuation system for drawing off the waste heat generated by the refrigerating machine have a relatively high weight and a relatively large installation volume. Moreover, their installation and, in particular, their integration into the installation space which is available on board an aircraft to a limited extent only, might be very complicated and require a high constructive expenditure. Finally, a spatial separation of the dispensing point from the reservoir containing the cooled drinking water is not possible, because the water which is contained in a conduit for connecting the dispensing point with the reservoir would be heated due to the higher ambient temperature. At least at the beginning of a dispensing operation, the water which is withdrawn at the dispensing point then would not have the desired cool temperature.
DE 33 34 103 A1 discloses a hot water supply device comprising a water heater which is connected with a cold water supply conduit. The water heater is connected with dispensing points via a supply conduit. From the dispension points a gravity circulation conduit leads back to the water heater.
From DE 90 04 046 U1 a device for heating or cooling of liquids is known, which comprises a reservoir for the heated or cooled liquid. Heating or cooling means may be arranged within the reservoir, either completely or with their heat exchanging components only. Alternatively, heating or cooling means may also be provided outside the container in the case of a reservoir which is employed as buffer container, with the container being connected in series to conduits of a heat circuit or a coolant circuit. A hot water boiler described in DE 90 04 046 U1 comprises heating means which are formed as a heat exchanger and are arranged in the reservoir interior, and which are connected with a hot water circuit of a building heating system.
DE 297 20 326 U1 describes an arrangement for heating the circulation water in a drinking water reservoir, wherein water which is contained in a reservoir is heated by a heating coil which is arranged in the reservoir or by a plate heat transfer means which is arranged outside the reservoir.
From DE 103 41 523 A1 a hot water boiler is known which is intended for use in an aircraft and operated as a flow heater.